Hyaloteuthis pelagica(Bosc 1802)

Introduction

Hyaloteuthis pelagica is one of the smallest ommastrephid species reaching a mantle length of 90 mm (Nesis, 1982/87) and may mature earlier than any other ommastrephid (46 mm ML mm ML for females - Dunning, 1998). Its maximum size is approximately the same as the dwarf Todarodes pusillus.

H. pelagica occurs in the upper 100 m at night but little is known about its daytime habitat although Young (1978) reported a mature female from 1,700-2,200 m captured in an opening-closing tow during the day off Hawaii. On one occasion, large numbers of mature H. pelagic were found stranded on a beach on Kauai, Hawaii (pers. comm.). Little is known of its general ecology.

Brief diagnosis:

19 large, round photophores on mantle.

Characteristics

Arms

Hectocotylus (Wormuth, 1976)

Hectocotylus may be on the right or left arm IV.

Hectocotylus with 12-15 suckers of which the distal 2-4 abnormally small.

Dorsal protective membrane, opposite last dorsal sucker, expands to form a flap then disappears; in same region, ventral membrane expands and thickens to arm tip without detectable trabeculae.

Figure. Ventral view of H. pelagica showing aberrant doubling at one photophore position (arrow). Photophore at posterior tip of mantle not obvious in this picture. Photograph by M. Vecchione.

Two round photophores on ventral surface of head, one at base of each arm IV.

Two spherical photophores in core of each arm IV located at 1/3 and 2/3 of arm length (difficult to see without dissection).

2 intestinal photophores.

Life History

Paralarvae

Dorsal head chromatophores tend to be very small, especially those in the mid-dorsal line. Young paralarvae with few large mantle chromatophores, typically one dorsal and one ventral.

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Figure. Ventral and dorsal views of paralarval stages and the first juvenile stage of H. pelagica. Drawings from Harman and Young (1985).

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Figure. Frontal view of the suckers at the tip of the proboscis of a paralarval H. pelagica. Photograph from Harman and Young (1985).

Adults

Fully developed hectocotylus may be present by 45 mm ML (Wormuth, 1976) and females can mature at least by 55 mm ML (pers. obs.).

Distribution

Type locality: Found within the stomach of a "dorade" in the open ocean.

Atlantic and Pacific Oceans and probably the Indian Ocean (Nesis, 1982/87). Occurs in tropical waters to warm temperate waters in the Pacific (Wormuth, 1976).

H. pelagica is an open-ocean species. Bower, et al. (1999) found that 35 % of H. pelagica paralarvae collected in Hawaiian waters were taken more than 200 km offshore and that paralarvae of H. pelagica belonged to an assemblage of oceanic cephalopod paralarvae rather than an Island-associated assemblage.

Modified from: Sasaki, M. 1929. A Monograph of the Dibranchiate Cephalopods of the Japanese and
Adjacent Waters. Journal of the College of Agriculture, Hokkaido Imperial
University, 20(supplement):357 pages.

Size

80 mm ML

About This Page

Page: Tree of Life
HyaloteuthisGray 1849. Hyaloteuthis pelagica(Bosc 1802).
Authored by
Richard E. Young and Michael Vecchione.
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